1. Field of the invention
Use is generalized, at the present time, for the purpose of transporting and storing very varied materials in loose form, to using movable containers consisting of a receptacle, the lower part of which has the shape of a hopper exhibiting a discharge orifice and a means for closing off this orifice. These containers are also equipped with an underframe for supporting them and allowing them to be transported by handling vehicles.
In known transfer installations, the receptacles or containers to be discharged are brought, by known means, above the discharge station so that their discharge orifice, closed off by a valve of known type, is situated above the upper orifice of a pipe serving a piece of apparatus, generally situated in another premises, or of another receptacle; simple manoeuvering of the valve of the container brings about the outflow of the products to be transferred to the piece of apparatus or towards the second receptacle.
Similarly, the container includes an upper orifice via which it can be filled from a piece of apparatus via a pipe placed above it or from another receptacle.
In general, in installations of known type, the connections between containers or pipes are carried out manually.
In these installations of known type, a certain amount of particles of the products to be transferred escapes into the ambient atmosphere, during the displacement of the container and the transfer of the product.
The consequences of this pollution may, in some cases, be dire, especially when these installations are involved in the feeding of machines used in the pharmaceutical field and, in particular, when there is a risk of cross-contamination or when there is handling of toxic products, among which mention may be made of hormonal products, products which cause an allergic reaction, cytostatic products or other products.
Another problem which exists, especially in the pharmaceutical and foodstuffs sectors, is that ensuring that products are transported and transferred under conditions of strict sterility, asepsis or very great cleanliness.
One of the problems to be solved, in this sort of piece of apparatus, therefore consists, especially, in producing, at all moments, and particularly during the connection and transfer phases, sealing which is as complete as possible of each receptacle or pipe individually, and between each receptacle or pipe and the surrounding premises.
Another problem consists in seeing to it that the connections and transfer of products are carried out without direct contact with the staff, and preferably, in an entirely automated fashion.
2. Description of the Prior Art
European Patent Application EP-A-0,384,826 discloses an installation for transferring products flowing out under gravity from the lower orifice of a receptacle into receptacles or machines situated at a lower level, through use of a vertical chute. The installation includes, on the one hand, a first plate mounted on guides joined to the chute, sliding between a position in which the upper orifice of the chute is covered over and a position in which this orifice is cleared, on the other hand, a second plate mounted on guides fixed to the container to be emptied, sliding relative to the latter, between a position in which the lower orifice of the container is covered over and a position in which the said orifice is cleared, means being provided so that, during the displacement of the container in a horizontal plane, the movements of these two plates sliding on their respective guides are synchronous, but in opposite directions of.
In its preferred embodiment, the synchronous movements of the two sliding plates are ensured directly by a horizontal translational movement of the container, and in particular with the aid of magnets.
One problem which is not solved in this installation is that, although during all the operations of displacement of the container and transfer of products the orifices of the container and of the chute are always covered over, sealing is not complete. Indeed, a slight amount of play must be maintained between the orifices and the plates which cover them over in order to allow these plates to slide. As a result, fine particles may still escape into the ambient air.
Furthermore, a direct communication still exists between the two orifices and the ambient atmosphere after the plates have been pulled back and before the union is made between the container and the chute.
Document EP-A-0,092,008 describes a device for transferring, material in loose form under gravity, from one container towards a discharge hopper. The lower orifice of the container is closed by a sliding cover, lined with a butterfly valve. A movable sleeve tube makes it possible to produce a sealed connection between the container and since the discharge hopper does not have closure means, this device does not make it possible to avoid a certain amount of transferred material being dispersed into the atmosphere.
Patent Application FR-A-2,077,451 describes a device intended to produce a leaktight joint between a container and a discharge station including a chassis provided with a fixed part and a movable part.
The device described in FR-2,077,451 also makes it possible to produce a leaktight joint between the two enclosures solely during the transfer phase, it does not make it possible to avoid contamination of the surrounding medium. The extent to which the device is hermetic as regards to the atmosphere is no longer ensured as soon as contact between the station and the container is broken; what is more, the station does not include a hermetic cover. Moreover, if particles infiltrate into the device during transfer, they may be dispersed into the ambient atmosphere.
DE-A-1,034,549 describes a union device intended to avoid the spread of dust during the transfer of solid materials between a hopper and a translocation vehicle, this device especially includes a system for sucking up dust. This suction device is not, however, separated from the two receptacles by a leaktight union; consequently, it is in direct contact with the materials transferred. Such a device does not avoid contamination between the hopper, the vehicle, and the atmosphere, which is contrary to the goal sought here.
FR-A-2,640,598 describes a device for transferring products, in which the devices for closing off two containers are mechanically coupled so as to ensure simultaneous actuation.
The hermetic nature of this device is provided solely by the juxtaposition of the two closing-off devices, which is insufficient to avoid any contamination with the atmosphere, it being especially possible for particles to become housed between the external faces of the two covers.
U.S. Pat. No. 3,870,168 describes a device for transferring powdered materials, which is equipped with an air curtain reducing the risk of a cloud of powdered particles escaping during the transfer of material. Such an air curtain applies only to certain types of transfer and does not in itself solve the problem posed here.
These various known transfer devices additionally do not make it possible to obtain sterile transfer.
Consequently, large work zones must be considered as "contaminated". It is therefore necessary to provide, often at high cost, devices for separating these zones from one another and for protecting the outside environment from pollution (limited access, decontamination zones, elaborate systems for filtering the ambient air, etc.).
It is also necessary to provide the workers moving around in these zones with adequate protective equipment.